Control knob and indicator



5 0 6, 2 9 6!v l F L O w E, R. om 2 9 1 0, 2 W` N CONTROL KNOB AND INDICATOR Filad May 8, 1926 2 Sheets-Sheet f l ira.

lllmell llllllllnmfE Y Nov. 20, 1928. 1,692,605

- R. E. woLF CONTROL- KNOB AND INDICATOR Filed May 8, 1926 2 sheets-sheet' 2 milk f `1,692,605 PATENT OFFICE.

ROBERT n. WOLF, or CHICAGO, rLLINo'Is.

coN'rnoLf xNoB AND INDICATOR..

,Appumion mea may s, 1926. serial. Nag-101,733.

This invention relates to improvements in control knobs and indicators for actuating shafts which areada ted to assume a plu`l rality of positions, an is particularly adapt-v ed foruse with the tunable elements of radio apparatus. I i f It has heretofore been proposed to provide knobs in conjunction with radio apparatus,

which by a train of reduction gearing, secure a minute adjustment of the tunable element-in a radio set. It has heretofore been customary, however,v to provide a dial for giving indication'of the instant position ofthe tunable element which was directly coupled' to the shaft of the tunable element, and in con' junction with an .indicator serving to designate the particular position of the respective parts.

junction with the dial scale to indicate fractional movements of lesser amount than a single scale division.

In oppos1tion vto these features in such devices, the present invention concerns the provision of a knob which is connected by a reduction train to the shaft of the tunableelement, and is `connected preferably by a speed-increasing train with an indicating device. In this way, a reduction of speed, and

thereby a slow movement, is aorded to theshaft of the tunable element, while onthe contrary the increased ratio from the knob shaft.

to the indicator occasions 'a multiplication of speed and permits the registration' of very4 slight movements of thel knob as large movements'of theindicator. H

In this connectionyit is preferred to employ as an indicator a tachometer or disk recorder of the type usual-in Odom-eters and revolution counters. Such instruments arel Y old and well known in the art, and are used as an example ofthe means of securing accurate indica-tions of the relative positions of the shaft of the tunable element and the shaft ofthe knob. y

This invention has been shown in several examples of execution in the illustrative presentation on the accompanying drawings, 1n which y i Figure .1 is a face view of a dial and indicator mounted upbn a panel, with the reduction train shown vin dotted lines. j

Fig. 2 is a section taken on line 2-2 of Fig.

Fig. 3

, Fig. -9is a section on line 9-9 of Fig.

It has heretofore 'likewise been proposed to employ a Vernier scale in con-v screw 16 in known ma'nner.

is a view of the dal and indicator modified form of the device, with the panel removed, to show the driving train for the indicator.

Fig. 7 yis a view on a smaller scale of the modified form shown in Fig. 6, employed in driving a plurality of condensers in bank.

Fig. 8 isa face view of a partial section of a further modified form.' A

Fig. 10-is a section through the transfer mechanism of the tachometer counters, substantially on line 10-10 of Fig. 11, on an enlarged scale.

Fig. 11 is a diametral section through two of these counters, on an enlarged scale. In Figs. 1 to inclusive, the dial and indicator are shown mounted upon a ypanel 10 which may be of insulating material. The

apparatus has the face plate 11 which is displayed on the outer side of the panel and which has two apertures therethrou h to receiveI respectively the knob shaft an a window covered by av transparent'plate 12 of glass for example, through which the indications of the counter wheels 13 may be observed.

The knob 14 is mounted upon a knob shaft 15 and held in invariable relation b a set Thekno shaft 15 passesthrough the customary bushing 17 which is held by its enlarged end against the face plate 11, and has its other end threaded .to receive the strap 18 forming a part of the rear frame of the apparatus. It will be understood that in assembling'the device upon a panel, the face plate is placed in position atthe front, and the rear assembly including the strap 18 at the rear of the panel, with the shaft 15 projecting through; the bushing 17 is then placed in position and is threaded home, usuallygby the use of a wrench on the enlarged head.-

The, strap 18, as shown in Fig. 5, is Yformed integrally with the rear strap 19 to which it is connected by the angle portion 20. The rear strap 19 and the portion to the rear of the tachometer disks is folded down at the sides to form a shield 21 for these disks;

flush against the end of the shield 21 and may be secured thereto by screws 33 which pass through and into these elements. The shaft 15 is journaled in the bushing 17 and the rear stra 19, as shown in Fig. 2. Securely pinne to the shaft 15 to turn therewith is the bushing 23 which has the pinion teeth 24 therein and the bevel gear 25 assembled therewith. The teeth 21 are few in number, and mesh with the teeth of the large gear 26 which is keyed in an appropriate manner upon the shaft 27 of the tunable element of the radio apparatus, which is to be accurately adjusted by the rotation of the knob 14. The gear 26 may have any suitable number of teeth to afford a proper ratio between the teeth 24 and itself tosecure the required sensitiveness and minuteness of adjustment.

In the particular instance here displayed, the shaft 27 is shown as belonging to a tunable instrument which in the particular instance is a variable condenser having the rotor plates 28, but it will be understood that this is merely by way of illustration. The shaft 27 in this instance is journaled in the end support 29 of this condenser.

The bevel gear 25 has a large number of teeth and drives the bevel gear 30 which is mounted on the shaft 31 of the tachometcr counters. The bevel gear 30 has a very few teeth so that it is operated at a relative increase of speed with respect to the knob shaft 15. The shaft 31 is connected directly to the right hand counter disk in Fig. 1 in known manner and in one complete rotation will move this disk so that the successive indicia from 0 to 9 or vice versa are displayed. In Figs. 10 and 11 has been indicated one form of transfer system which may be employed between the respective disks. The right hand counter disk '80 in Fig. 11 is mounted for loose rotation about a stub shaft 81 which has a fiat on one side. The adjacent counter disk 81 is likewise mounted. The right hand counter disk 8O is driven from the bevel gear 30 by a plate 82 so that it moves by the same angular distance as the bevel gear 30. On its lefthand side in Fig. 11, the first counter disk has two teeth 83 (Fig. 10) which mesh once in each revolution of thc disk 80 Vwith the transfer pinion 84 which is pivoted on the pin 85 carried by the filler plate 86 which in turn is held fixed with the shaft 81 by seating the flat thereon. The pinion 81 projects beyond the edge of the counter disk 8O` into a recess formed in the right hand face of the counter disk 81. This recessed face of the disk 81 is provided with twenty teeth 87 (Fig. 10). The left hand side of the counter disk 81 is again formed with two teeth corresponding to teeth 83, toengage a second transfer pinion 84* on the pin 85n of the filler plate 86. As a result of this construction, as the right hand disk 80 completes a. full revolution, its two teeth 83, cause a.

movement of the pinion 84 by two teeth, which causes a movement of the second coun; ter disk 81 by two teeth, which is 2/20ths or 1/10th of a revolut-ion of this disk, and

corresponds to a transferby one digit of the indicia yupon its face. i. e., the disk 81 moves for example from O to 1 or from 1 to 0, according to the direction of movement of the bevel gear 30. The same action occurs between this latter disk 8.1 and the one to its left, etc. Such transfer mechanisms are old and well known in the art and are not claimed except as they form a part of the combination according to this invention.

The panel 10 is cut away at two points for a. small round aperture to receive the bushing 17 and an oblong aperture to receive the shield 21 for the counter wheels, and it will particularly be noted that the face plate is clamped upon the panel by the employment of the single bushing 17, so that the device may be easily and quickly mounted upon or dismounted from a panel.

The device shown in Figs. 6 and 7 is but slightly modified from that already described in that it is applicable to the driving of a plurality of condensers arranged in bank with a. common shaft disposed with its axis parallel to the face )anel of the radio apparatus. The shield 21 r the counting wheels 13 is substantially the same as that already described` and a shaft 31u is provided which is of greater length than that already described at 31. This shaft is journaled by outstanding lugs 31h to the panel 10 shown in Fig. 7. A face plate 11 is provided for the face of the panel opposite the shield 21, and a window 12l through which the counter wheels may be observed. The knob 14*JL is mounted uponwa shaft 15IL which carries a worm 24 which is in mesh with a large worm gear 26. The=worm wheel 2 6* is preferably split or otherwise mounted on an insulating bushing 26 which is used to connect the several condenser shaft sections 27, 27. Further insulating bushings 26c may be employed for connecting further sections '27c of the condensers to the sections 27h, 27 already described. VThe shaft 15* is suitably journaled on the hearings 19ll which are usually connected to the base-board of the radio apparatus. l

The spider 25" is rigidly keyed to the knob shaft 15a and has a plurality of fingers 26" which engage withv the driving pinion 30* which in turn is keyed to the shaft 31B.

The method of operation of this device is the same as that of the form already described, from which it differs partly in that the condensers vor other tunable elements may be arrangedn bank with the common axis parallel to the face panel, and in the further feature that the knob 14 maybe disposed at one side of the panel, whilelthe indicator having the counter disks 13 may be disposed in a lo nal teeth^56 which are cut along the ledge/of a slot 57 in a rear'disk 58 mounted within the hollow face plate 53, 54. {This disk 58 has a vcentral hub 59 which is rigidly keyed to the driving shaft 60 of the tunable element in the lradio set. For appearance, itis preferred to provide an end cap 61 whichis secured to the outer end of ,the shaft 60 and assists in supporting the faceplate 53, 54`in its proper position upon the panel. j

The disk 58`is likewise formed with the external teeth 62 which mesh with the small' pinion 63 carried on shaft 64 which is journaled ona lug 650m the interior of the face plate 53, 54, and' at" its other end carries a evel lgear 64 which meshes with a similar .i bevel gear 65 mounted on the shaft 66, which 1n Fig.` 9. .-Inorder to protect andsupport the l n, counter wheels 70 and the shaft 66 at its bearn ing 71, a rearshield 75 is provided to contain them, which may be connected by any appropriate means not shown Ato the face plate 53, 54. f

It will be seen that the panel 10b in this instance again has twoapertures, one for the shaft of the tunable elements, and the other alarger oblong aperture to receive the shield v 75 which contains the counting wheels.

Since the presently employed frequencies at broadcasting stations range from 500 to 1500 kilocycles per second, it ispreferred to so select the constants of lthe radio apparatus that a half or other predetermined portion of arevolution of the shaft 0f the-.tunable element willeffect successive responses to waves within these frequencies, and it is particularly valuable to employ this device with four counter wheels in connection with straight cuits wherein the kminimum capacity repref sents a resonance at y1500 kilocyclesand the lmaximum capacity a `resonance at 500 kiloline frequency condensers associated in cicycles, the counter wheels being set at 500 kilocycles for themaximu'm capacity position of the condenser and gear trains, and addform shown in Figs. 8 and v e usual manner. Theingtlie successive increments of'rotation'alv 65 movement ofthe knobin decreasing capacity, so thaty the counter wheels at all times indicate exactly andvdirectlyv the'frequency of reso i nance. The three counter wheels at the 'left move by steps, while the right hand wheel, be-

ing directly geared, responds immediately and bya vrelatively large movement to any actuation f'the knob in either direction. It is apparent, however, that the device is not limited solely to such employment.

l It is obvious thatv the invention fis not limlted solely to the illustrations given, but

may be modified within the scope of the appended claims. y

I claim: s 1. In a radio apparatus, a tunable element having a shaft, a knob, a speed reducing train connecting said knob and said shaft, an indicating device independent of said shaft, and a speed multiplying train connecting said knob and said indicating device whereby said knob actuatessaidelement at a speed lower than its own and said indicating device at a speed higher than its own so that a small movement of said element corresponds toa large movement of said indicating device.

2. `In a radio apparatus, a tunable element having a shaft, a `face plate, a knob shaft journalled in said face plate, a knob on said knob shaft, a first gear on said knob shaft, a gear vhaving a greater number of teeth than said first gear and fixed on said element shaft in mesh with said first gear, a counting mechanism having a shaft, a Second gear on said knob shaft, and a gear having a lesser number of teeth than said second gear and fixed on said counting shaft in mesh with said second gear whereby said knob actuates said element at a speed lower than its own and said inditween said knob and the lowest unit of said counting wheels whereby said wheel moves with said knob, and the others of said wheels move stepwise withv respect to said 'lowest unit wheel so that-said indicators` indicate directly by their divisions the resonance frequencies of the circuit containing said variable condenser. f

4. In afknob and izo indicating apparatus, av l knob, a' tachometer having 'a plurality of counting wheels with stepwise transfer` mechanisms, a speed multiplying transmission connecting', said knob and the lowestv unit of said tachometer,`and an independent speed reducing transmission between said knob and the shaft of a variable element, whereby said knob directly drives said tachometer unit at a multiple of its own angular movement, and said shaft at a speed which is a fraction of its own angular movement.

5. In a knob and indicator apparatus, a face plate, a housing fixed to the rear of said face plate, a bridge member fixed to said housing, a knob shaft j ournaled in said face plate and bridge, a knob on said shaft in front of said face plate, na gear on said shaft between said face plate and bridge, tachometer Counting wheels in said casing, and means whereby said gear can drive the lowest unit of said counting wheels.

6. In a knob and indicator apparatus, a face plate havinga window therein, a casing connected to the rear of said tace plate, tachometer counting wheels in said casing, a knob shaft passing through said face plate, a knob onsaid shaft in front of said plate, and connections whereby said shaft may drive the lowest unit of said counting wheels, said coiuiting wheel being displayed through said window.

In testimony whereof, I aix my signature.

ROBERT E. WQLF. 

